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	<title>数学对象</title>
	<script type="text/javascript">

		var res = Math.abs(-89.78);

		var res = Math.ceil(89.0000001);

		var res = Math.floor(89.999999);

		var res = Math.round(89.67);

		var res = Math.round(Math.random()*100);


		var res = Math.round(Math.random()*(47-1)+1);

		document.write(res);

		作业：从1-47中随机产生7个不重复的数

	</script>
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